Material coating apparatus



June 19',4 194.5. H, E, 'lx'HORNToN v A 2,378,599

MATERIAL COATING APPARATUS Filed Aug. 10,1943 :s sheets-sheet 1l Hei/ y June 19, 1945.v

H. E. THORNTON MATERIAL COATING APPARATUS Filed Aug. l0, 1943 3 Sheets-Sheet 2 /NVENTQQ Hf. mom/TON ATTOENE Y June 19, 1945. H E, T-lQRNTON 2,378,599

MATERIAL COATING APPARATUS Filed Aug. 1o, i943 3 Sheets-Sheet 3- ATTORNFY Patented June 19,1945 5 I vUNi'rlio STAT-'E PATENT 'oi=ric:ie'.ffl

MATERIAL ooA'riNG AreAaArUs f Harry E. Thornton, Plainfield, N. J.`,assignor to -Western Electric Company, Incorporated, New York, N.' Y., a corporation of New York 2 claims. l(o1. 91-7'13 invention relates'to material coating apl pertatus, `and more particularly to apparatus for t ,forming a coating of dried liquid materialon ,material in tape or ribbon form. f

V'Ihere are innumerable instances in the karts. 1

where it is desired to yform a coating ,ofdried liquid material Vor iinelydivided solidmaterial yin a liquidvehicle on the surface of a sheet ribbon. of solid substance.

In a particular instance, inthe manufacture of laminated cores of magnetic substance for electromagnetic coils,

it is sometimes desired to coat one facefof a tape orribbonof magnetic alloy with mineral powder, e. g. iinely divided mica., This may lbe done by -sprayingor .otherwise coating onek face of the i5 tape with a suspension4 of the powdered mineral in a suitable liquid vehicle, e. g. one per cent (1%) of polyvinyl alcohol in water, and then heating the'coated tape to drive off the Water.

An object. of they present inventionY is to'y prol.vide a simple, reliable apparatus for coating material in 'tape form ,by heating the tape, covering A`one face of the. hot tapewith liquid coating material, and continuingthe heating to drive off the .liquid vehicle of the coating.

` 1 With theabove and other objects in view, the

invention may be embodied in an apparatus for coating one side of a tape of magnetic lmaterial and comprising capstan means including a drum 4tofreceive and advance a longitudinally movable tape,y meansfto heat thetape supporting surface of'theidrum, and lmeans vto apply liquid coating v material on the free surface ofthe tape on the drum Other objects and features of the invention :35 willappear from the following detailed description'ofone embodiment thereof taken inconnectionwith .the accompanying drawings;

` which the same reference numerals are applied I to identical parts the several figures and which Fig. ,l is a view iny 40 inside elevation, with parts broken away, of a tape coating apparatus embodying the invention;

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig.l3 is a section on the line 3&3 of Fig. 1;

Fig. 41s a detached enlarged view in side elevation of the takeupl drum;

' Fig. 5 is a partial end view thereof on the line 5-5 0f Fig. 4;

Fig. 6 is a partial view corresponding to Fig.

of amodifled form; and

Fig. '7 is a section on the line 1-1 of Fig. r6.

' The heart of the apparatus is the rotary drum` 20 or `|2|| over which runs the tape I9 to be coated' and dried. The `cylindrical Wall 2| or |2| of the drum has a smooth outer face on which the tape |9lies.; The wall 2| is heated from the inside, cfg. by electrical heating units 22 'as inFig. 2, and the Wall |2| by fuel burners |22v as in Fig. '1. 'I he electrical units 22 are attached to the inner face of the wall 2| and travel with, it, being fed with current through slip rings. 23 rotating with lthedrum and brushes v24 mounted in a suitable staticnarybox 25 secured on the machine frame. The burner units |22 are stationary within the ydrum |2|lv which travels around them.v The apparatus is enclosed generally in a housing 26. The tape I9 comes to the apparatus from a supply not shown, enters the housing through an appropriate aperture and passes `under a guide roller 21. A correspondingly curved, stationary guide member 23 serves to guide the end 'of a new tape being brought in around the roller 21. The tape comes .'tangentially off the roller 21 and goes tangentially on the drum face 2| ata point about .forty-five degrees (45) below horizontal. Thence it runs l along on the drum under a pressure roller 29 y held against the tape on the drum by a spring 30, and which can be lifted and held away from the drum by a hook 3i when a iresh end" of tape is being vthreaded through the machine. After passing the roller 29, the tape on Vthe drum face 2| may be subjected to a suitably intense flame 432 from` a burner33 to remove combustible dirt and especially grease or oil from the surface to be coated. The tape continues on thence, lying snugly against the .hot face 2| or |2| of the drum to be heated thereby. At or a little. past the top of thel drum,.the tape on the drum passes under one or'more means tocoat the outer surface of the -tape with a liqueform material, e. gy. mica ypowder suspended in one percent (1%) polyvinyl alcoholin water. VThese means are shown -here as spray nozzles 34... The coated,1hottape passes'thence, stillon the drum, tov a point about pleted by the time the tape leaves the drum 20 at the left to pass to the takeup drum or'core'35.

The drum or core 35 is essentially a split ring.

as best seen in Figs. l and 5. The drum surface proper 38 is a cylindrical sheet slotted from end to end at 39. A spring member 46 secured against the inner face of the cylinder 38 tends to expand the latter in diameter. Such expansion is limited to a maximum amount by a toggle linkage 4I, 42 when in the position thereof shown in Fig. l. At the slot 39, one end of the cylindrical sheet 38 is provided at each end of the slot with guide lugs 43, 44 between which the other end of the sheet 38 is kept properly aligned. Normally when in use, the drum 35 has its maximum diameter as indicated in Fig. 1 and the coated tape winds up snugly on it with the coated side inside and the bare side of the tape running on the driving rolls 36 and 31. When a length of tape has been Wound and the coil so formed has been bound externally with a circumferential binding cord or Wire, the toggle 4|, 42 may be actuated by a handle lever 45 to close theslot 39 and thus di-` `minish the diameter of the takeup roll 35 to per- -mit the latter to be easily drawn axially out of the coil of tape.

Scraping means, such as a sharp doctor blade 46, and smoothing means, such as a brush 41, are mounted to be pressed resiliently, as shown, against the surface of the drum 20 at the bottom thereof to keep the same clean and smooth.

A motor 48, working through a slippable belt device 49, drives a variable speed mechanism 56 from which the drum 20 and the rolls 36 and 31 are driven by suitable chain and sprocket drives. These drives are so constructed that the peripheral speed of the rolls 36 and 31 is a trifle greater than the peripheral speed of the drum 26. Hence these rolls keep a constant tension on `the tape which keeps the latter firmly down on the drum 26 throughout the contact of the tape with the drum. The back pull for this tension is provided by the bending of the tape around the roller 21. Because of the great area of contact of the tape' on the drum 20, the tape will not slip on this drum. The rolls 36 and 31 slip under the tape. Thus the drum 20 is, in effect,` a threequarter turn capstan, for which the rolls 36 and 31 slipping under the tape provide the friction effecting pull and the roller 21 provides the back pull. The tape is advanced through the apparatus by the drum 20, and hence the speed of advance of the tape is not affected by the varying diameter of the body of tape coiled on the takeup drum 35. Hence it is preferable that the tape pass over a considerable arc of the roller 21 in order that sufficient back pull be provided thereby to enable the drum 26 to act as a capstan.

The apparatus illustrated in the accompanying drawings is capable of handling two similar tapes simultaneously, as is evident from the drawings, although'only one tape is shown as being treated. Operation of the apparatus has been described in connection with the coating of a tape of magnetic material with mineral powder suspended in a liquid vehicle. However, the invention is not limited to this particular application but is believed to be adapted for use in a Wide range of cases Where relatively long strips, tapes or sheets of material are to be coated with an initially fluid and heat-dryable coating material. Hence the Word tape in the appended claims is lto'be thought of as including generally any flexible laminar elongated article which can be passed over rollers and drums such as 21, 20 and 35, provided the latter are made of axial dimensions suitable to the transverse Width of the tape vWhat is claimed is:

l. An apparatus for coating one surface of a metal tape and comprising a capstan drum to receive and advance a longitudinally movable tape, a freely rotatable guide roller driven by the advancing tape and to receive the tape advancing to the apparatus and to deflect the direction thereof around a considerable arc of the roller to provide back pull inthe tape while guiding the same tangentially to the drum, means to lclean the outer surface of the rst portion of the tape running on the drum, a core to receive'the advancing tape from the drum and coil the same, Va pair of supporting and driving rolls to support and drive the coil on the core, means to drive the drum and the pair of rollsv so that the peripheral speed of the rolls is greater than the peripheral speed of the drum to drive the coil to exert a forward pull on the tape on the drum to ensure the capstan effect of the drum, in combination with means to heat the tape supporting surface of the drum, and means to apply liquid coating material on the cleaned portion'of the free surface of the tape on the drum.

2. An apparatus for coating one surface of a metal tape and comprising a capstan drum to receive and advance a longitudinally movable tape, a freely rotatable guide roller driven by the advancing tape and to receive the tape advancing to the apparatus and to deflect the rdirection thereof around a considerable arc of the roller to provide back pull in the tape While guiding the same tangentially to the drum, a burner to clean the outer surface of the first portion of the tape running on the drum, a core to receive the advancing tape from the drum and coil. the same, a pair of supporting and driving rolls to support v and drive the coil on the core, means to drive the HARRY E. THORNTQN. 

